Phylogenetic diversity is a better predictor of wetland community resistance to Alternanthera philoxeroides invasion than species richness

• Highly biodiversity communities have been shown to better resist plant invasions through complementarity effects. Species richness (SR) is a widely used biodiversity metric but lacks explanatory power when there are only a few species. Communities with low SR can have a wide variety of phylogenetic diversities (PD), which might allow for a better prediction of invasibility.
• We assessed the effect of diversity reduction of a wetland community assemblage typical of the Beijing area on biotic resistance to invasion of the exotic weed Alternanthera philoxeroides and compared the reduction in SR and PD in predicting community invasibility.
• The eight studied resident species performed similarly when grown alone and when grown in eight‐species communities together with the invasive A. philoxeroides. Variation partitioning showed that PD contributed more to variation in both A. philoxeroides traits and community indicators than SR. All A. philoxeroides traits and community indicators, except for evenness index, showed a linear relationship with PD. However, only stem length of A. philoxeroides differed between the one‐ and two‐species treatments, and the diversity index of the communities differed between the one‐ and two‐species treatments and between the one‐ and four‐species treatments.
• Our results showed that in natural or semi‐natural wetlands with relatively low SR, PD may be a better predictor of invasibility than SR. When designing management strategies for mitigating A. philoxeroides invasion, deliberately raising PD is expected to be more efficient than simply increasing species number.

     

Characterization of <Emphasis Type="Italic">SWEET</Emphasis> family members from loquat and their responses to exogenous induction

The plant SWEET family is a sugar transporter family that plays a significant role in plant development. Here, seven loquat SWEET family members were identified by RNA-seq. These were designated as EjSWEET1, EjSWEET2a, EjSWEET2b, EjSWEET2c, EjSWEET4, EjSWEET15, and EjSWEET17. Phylogenetic and predictive functional annotation analyses suggest that the loquat SWEETs are classified as having sucrose, glucose and fructose transportation features. The in vivo responses of loquat SWEETs to exogenous sugar or NaCl was investigated by applying high concentrations of sugar or salt to 7-month-old loquat seedlings cultured in a nutrient medium. The results showed that most loquat SWEET genes can respond to exogenous applications of sucrose, glucose, fructose and salt. The response of EjSWEET1 to exogenous fructose was faster than the others, indicating that EjSWEET1 is more sensitive to exogenous fructose compared with other loquat SWEETs. EjSWEET15 can be induced by sucrose, but is suppressed by glucose. This indicates its possible role in sucrose transporting. The response of loquat SWEETs to NaCl showed broadly similar patterns compared to sugars. However, after a longer time of NaCl treatment, most loquat SWEETs are upregulated, especially EjSWEET15. This indicates its long-term response to high salinity.     

Accelerating Neuroimage Registration through Parallel Computation of Similarity Metric

Neuroimage registration is crucial for brain morphometric analysis and treatment efficacy evaluation. However, existing advanced registration algorithms such as FLIRT and ANTs are not efficient enough for clinical use. In this paper, a GPU implementation of FLIRT with the correlation ratio (CR) as the similarity metric and a GPU accelerated correlation coefficient (CC) calculation for the symmetric diffeomorphic registration of ANTs have been developed. The comparison with their corresponding original tools shows that our accelerated algorithms can greatly outperform the original algorithm in terms of computational efficiency. This paper demonstrates the great potential of applying these registration tools in clinical applications.     

Ultra‐sensitive fluorescent sensor for intracellular miRNA based on enzyme‐free signal amplification with carbon nitride nanosheet as a carrier

A novel ultra‐sensitive fluorescent sensor for monitoring microRNA (miRNA) in living cells was constructed by utilizing a hybridization chain reaction (HCR) as the signal amplification with a carbon nitride nanosheet (CNNS) as a carrier. The Cy5‐labeled hairpin DNA could be adsorbed onto the surface of CNNS, resulting in fluorescence quenching of Cy5. When treated with complementary miRNA, the fluorescence was recovered because miRNA could efficiently trigger an HCR, which led to the release of the HCR products from the CNNS. This intracellular HCR strategy can be used for ultra‐sensitive monitoring of intracellular miRNA. The main advantages of the proposed method are its simplicity, high sensitivity, high specificity and low toxicity for monitoring low‐level biomarkers.     

The EF‐1α promoter maintains high‐level transgene expression from episomal vectors in transfected CHO‐K1 cells

In our previous study, we demonstrated that episomal vectors based on the characteristic sequence of matrix attachment regions (MARs) and containing the cytomegalovirus (CMV) promoter allow transgenes to be maintained episomally in Chinese hamster ovary (CHO) cells. However, the transgene expression was unstable and the number of copies was low. In this study, we focused on enhancers, various promoters and promoter variants that could improve the transgene expression stability, expression magnitude (level) and the copy number of a MAR‐based episomal vector in CHO‐K1 cells. In comparison with the CMV promoter, the eukaryotic translation elongation factor 1 α (EF‐1α, gene symbol EEF1A1) promoter increased the transfection efficiency, the transgene expression, the proportion of expression‐positive clones and the copy number of the episomal vector in long‐term culture. By contrast, no significant positive effects were observed with an enhancer, CMV promoter variants or CAG promoter in the episomal vector in long‐term culture. Moreover, the high‐expression clones harbouring the EF‐1α promoter tended to be more stable in long‐term culture, even in the absence of selection pressure. According to these findings, we concluded that the EF‐1α promoter is a potent regulatory sequence for episomal vectors because it maintains high transgene expression, transgene stability and copy number. These results provide valuable information on improvement of transgene stability and the copy number of episomal vectors.     

臭氧浓度升高对坪用高羊茅生长、亚细胞结构及活性氧代谢的影响

通过开顶箱(OTCs)模拟,以环境臭氧(O₃)浓度约40 nmol·mol^-1为对照,研究大气O₃浓度升高(80和160 nmol·mol^-1O₃)对冷季型草坪草高羊茅生长、亚细胞结构及其活性氧代谢的影响.结果表明: 14 d的80 nmol·mol^-1O₃熏蒸使高羊茅株高和叶宽降低,总生物量降低43.7%,老叶变黄,而160 nmol·mol^-1O₃处理高羊茅叶出现大量枯死褐斑,叶尖坏死,新叶卷曲,总生物量降低46.2%,叶肉细胞膜卷曲,叶绿体和线粒体受损严重.与对照相比,80和160 nmol·mol^-1O₃熏蒸下高羊茅叶片超氧阴离子(O₂^-·)产生速率、过氧化氢(H₂O₂)和丙二醛(MDA)含量显著增加,抗氧化酶活性显著升高,但叶片总酚含量和抗氧化能力随O₃浓度升高而先升高后降低.在明显O₃伤害症状出现之前,O₃已对高羊茅的生长和抗氧化代谢产生不利影响;高羊茅抗氧化系统虽对O₃浓度的升高存在一定的适应性反应,但其不能抵御过高浓度的长期胁迫和伤害.